In recent years, various battery powered portable electronic apparatuses such as a tablet device, personal digital assistant (PDA), and smartphone have been developed. Many electronic apparatuses of this kind include touchscreen displays in order to facilitate input operations by users.
A user can instruct an electronic apparatus to execute a function associated with a menu or object displayed on a touchscreen display by touching the menu or object with a finger or the like.
This input operation using the touchscreen display is not limited to the operation of giving operation instructions to the electronic apparatus, and is also used to input documents by handwriting. Recently, users are beginning to attend meetings by carrying electronic apparatuses of this kind, and make notes by inputting handwriting on touchscreen displays. Various methods have been proposed for processing pertaining to this handwriting input.
When drawing a character or picture on a touchscreen display with a stylus or finger, the input data is processed by software including an operating system (OS), and a delay of about a few ten to 100 ms is produced until the character or picture is actually displayed on the touchscreen display. This delay spoils the writability of handwriting input on the touchscreen display.
As a measure to improve this, it is possible to predict the direction and size (length) of the extension of a line segment from a previous handwriting. It is, however, needless to say that any prediction sometimes goes wrong, so demands have arisen for a method of reducing user disconcertment if prediction goes wrong.
Also, a process of performing correction only when prediction goes wrong requires an extra calculation cost in order to detect whether prediction is right or wrong. Depending on a correction method, a drawn line segment may be different from a user's handwriting (the drawn line segment may come off the actual data input position under the influence of, for example, extra smoothing for making a wrong prediction inconspicuous). Accordingly, demands have arisen for a method of providing a user with a good feel of writing having a high response performance by using a predicted line segment, without increasing the calculation cost or causing user disconcertment.